code: def step(self, state, x=None, y=None):
      v = pyro.sample("v_{}".format(self.t), dist.Normal(0.0, 2.0))
      with pyro.plate("plate", self.plate_size):
          pyro.sample("w_{}".format(self.t), dist.Normal(v, 2.0))
      self.t += 1
  
imports: import pytest
  import torch
  import pyro
  import pyro.distributions
  import pyro.poutine
  from pyro.infer import SMCFilter
  from pyro.infer.smcfilter import _systematic_sample
  from tests.common import assert_close
label_desc: Use image node_id 3 for calling the SmokeGuide obj's underlying member method code with example usage: obj.step(state, x, y) without return types